what are the favored geometrical arrangements for abn molecules which the A atom has 2, 3, 4, 5 and 6 pairs of electrons in its valence shell?
2 is linear. 3 is trigonal. 4 is tetrahedral. 5 is trigonal bipyramidal. And 6 is octahedral.
what's abn mean?
I guess A is one atom, B is another atom, what's n. Perhaps the number of B atoms? Or is that supposed to stand for the number of unpaired electrons?
A is the central atom and B is an atom bonded to the central atom. n is the number of B atoms.
To determine the favored geometrical arrangements for ABN molecules, where A represents the central atom and B represents the surrounding atoms, we need to consider the valence electrons of the central atom. The number of valence electron pairs on the central atom determines the molecular geometry.
Here are the favored geometrical arrangements for different numbers of pairs of electrons on the central atom A:
1. A atom with 2 pairs of electrons (linear geometry): In this case, the molecule will have a linear shape, with the B atoms arranged in a straight line. The bond angle between the B atoms is approximately 180 degrees.
2. A atom with 3 pairs of electrons (trigonal planar geometry): The molecule will have a trigonal planar shape, with the B atoms arranged in a flat triangle around the central A atom. The bond angles between the B atoms are approximately 120 degrees.
3. A atom with 4 pairs of electrons (tetrahedral geometry): The molecule will have a tetrahedral shape, with the B atoms arranged in a 3-dimensional pyramid around the central A atom. The bond angles between the B atoms are approximately 109.5 degrees.
4. A atom with 5 pairs of electrons (trigonal bipyramidal geometry): In this case, the molecule will have a trigonal bipyramidal shape. It consists of a flat triangular base with the B atoms and two additional B atoms arranged in a vertical direction above and below the base. The bond angles between the equatorial B atoms are approximately 120 degrees, while the bond angles between the axial B atoms are approximately 90 degrees.
5. A atom with 6 pairs of electrons (octahedral geometry): The molecule will have an octahedral shape, with the B atoms arranged in a 3-dimensional arrangement around the central A atom. The bond angles between the B atoms are approximately 90 degrees.
To determine the specific molecular shape within these geometries, we also need to consider the presence of lone pairs on the central atom. The lone pairs can influence the bond angles and molecular shape further.